The South-Korean born Nam June Paik was considered to be the first video artist, and developed the idea of an electronic superhighway in 1974. This 49-channel closed-circuit video installation is Paik's retort to America's obsession with television, the moving image and all things bright and shiny. (JL)

Samuel Palmer - The Sketchbook of 1824, Early Morning (1825)

William Blake's rurally inclined friend, Palmer created some of the most seductive images of the English countryside. The subjects tend towards the predictably idyllic: the sentimentality of fly-free picnics, reclining poets and the dignity of the farmer's lot. Yet Palmer's delineation of infinite natural variety raises the atmosphere to visionary heights. The sketchbook, an extraordinary document of almost unhinged passion for nature, contains surely the most uncanny drawing of a donkey in all art history. Every patterned texture of Early Morning comes across as if swarming with organic energy. (RC)

Parmigianino - Self-Portrait in a Mirror (1524)Madonna of the Long Neck (1534-1539)

To draw his own portrait Parmigianino has looked into a convex mirror, and his painting is a simulacrum of that mirror - a round picture in which we see a distorted room, with the artist's drawing hand huge in the foreground.

These kinds of daring surprises are typical of the style called mannerism that developed in Italy as soon as the Renaissance ideals of proportion and perspective had been achieved; distortion, as in Parmigianino's Madonna of the Long Neck, was now the only way now for young artists to go. (JJ)

Martin Parr - New Brighton (1983-1986)

At the time, Martin Parr's series of photographs from New Brighton, a dilapidated seaside spot on the Wirral, were attacked as condescending. But now they look humorously engaged and fond, bringing British working-class nooks and crannies into view, and reminding us how unusual that was (and is) in art photography. (EM)

Vong Phaophanit - Neon Rice Field (1993)

Laos-born Vong Phaophanit was nominated for the Turner prize in 1993, and the work he created for the exhibition, Neon Rice Field, consisted of undulating lines of rice lit from beneath, emitting a seductive glow. Phaophanit's installations meditate on the transience of life, memory and loss. (JL)

Pheidias (and workshop?) - Parthenon frieze (c440BC-435BC)

A masterpiece of fluid, beautifully composed sculpture, the "Elgin marbles" ran in a 160m ribbon around the Parthenon. The frieze depicts a procession with horses and sacrificial animals culminating in a rather opaque religious ritual.

Though it is one of the most celebrated artworks in the world, the first guidebook to Greece, written in the second century, didn't even mention it. (CH)

Philippines (19th century - Angular wooden figure from northern Luzon

This little black wooden figure, depicted clasping its knees, was once part of a collection owned by the French surrealists André Breton and Paul Eluard. The mystery as to the precise origin of it remains, yet it is believed to be from the Ifugao people, who lived in the northern highlands of the Philippines. (JL)

The only reason to deny the title of the greatest artist who ever lived to Pablo Picasso would be a feeling, deep down, that he is less emotionally profound than, say, a Rembrandt or a Goya. And this suspicion would arise from the very thing that makes him so dazzling - his formal inventiveness. Picasso created entirely new visual languages, abandoned them, invented new ones, returned to his previous ideas in new ways, in a flow of creative ecstasy that only faltered late in his long life - and even when the stream mellowed it was still his.

There is a joy in life in Picasso's art that defies both the melancholy of his Spanish heritage and the sophistication of his adopted Paris. Perhaps the best place to begin, for anyone who wants to look at Picasso afresh and get the measure of his extraordinary talent, is to look at his series of etchings created in the 1930s for the legendary art dealer Ambroise Vollard: the bold, clear line in which Picasso can draw is as perfect as Raphael's but he does not rest on that perfection - not for a second. He invades it with a stormburst of violent forms: bulls gore horses in the arena, monsters appear to young girls, lovers crush one another as the god of styles plays at will with cubism, surrealism, classicism.

By the time Picasso etched the Vollard Suite he could draw on vast experiences and achievements. Recognised as a genius in childhood (here was not an artist who had to wait for recognition) he chose the tough life of the avant-garde, in Barcelona and Montmartre, living in poverty, painting his Blue Period laments - the first, brilliantly sentimental evidence of the social and political compassion that accompanies his creative urge. With Georges Braque, he embarked on his experiment in cubism, the total dismantling of western art's pictorial tradition: his cubist paintings demonstrate that experience is infinitely stranger and more complex than anything that can be simplified into a neatly organised picture. From now on, no visual appearance is taken for granted by Picasso. Everything is pulled apart and remade - he touches things with his eye, and gives them to you to touch as well.

No view of Picasso as an artist who rapidly declined or jumped about too much holds up to the testament of his art. The point about Guernica, the great history painting he made in a rage of compassion and solidarity with the Basque town bombed by the German air force during the Spanish civil war, is that it is a natural development from mythological scenes he'd been imagining in the 30s under the influence of surrealism and his own dark side. It is, as a humane statement about war, unmatched in art.

This account began by wondering if Picasso might be denied the title of the world's greatest artist because he seems to lack the spirtuality of a Rembrandt, the truth of a Goya. He doesn't have "soul", that's true, because he was an atheist. But his late Self-Portrait is no less moving for that. As for truth, as for humanity, as for the full translation of life as he knew it into art - who ever did anything like as much? He matches the genius of High Renaissance masters, yet also lets the brutal savage energy of real life into the studio. The science in cubism outstrips Leonardo's researches. What other artist in history can really compare to the greatest of them all? (JJ)

Giovanni Battista Piranesi - Imaginary Prisons (1750)

Piranesi's etchings pictured Kafkaesque architectural complexes almost two centuries before The Castle and The Trial were written. With an incisive command of suspenseful stage management, Piranesi sets up doors that open onto nightmare precipices and stairways that end in mid-air nowhere. A vertiginous psycho-architecture. (RC)

Antonio Pisanello - St George and the Princess (c1437-8)

The chivalrous dreams of the middle ages are given a reality and substance by new ways of making figures solid and portraits lifelike in Pisanello's art. His St George is an Arthurian knight in a deeply compelling landscape. (JJ)

Nicola and Giovanni Pisano - Pulpits (13th/early 14th century)

The heroic forms that swarm these precocious works of medieval sculpture, inspired by ancient Roman sarcophagi that can still be seen today in Pisa's Campo Santo, anticipate and influenced the Renaissance recovery of the classical nude. (JJ)

Camille Pissarro- The Red Roofs (1877)

The village houses glimpsed through winter trees, their russet rooftops and pale walls tantalising and moving - who lives there? - show how much Cézanne owed to Pissarro, in whose hands impressionism is a sombre rustic art. (JJ)

Polke went from ironically paying tribute to consumer hotdogs, as a kind of eastern bloc Pop artist, to conjuring some of the most contagiously gripping chemically tinged hallucinations of our time. His Ben-day dots tend to be painstakingly hand-painted. His dream images overlap and cross-associate. The unnerving tension of these two works lies in their thematic ambivalence, hinting simultaneously at things both dreadful and intoxicating, world-weariness and playful innocence. No one else comes near Polke's sophisticated orchestration of unease. (RC)

The moving thing about the man who "broke the ice" for modern art in America is the contrast between his hugely painful, thwarted life and the almost miraculous grace he briefly achieved in his art. What makes this one of art's great and mysterious stories is the clarity with which you can see this heroic tale in Pollock's own paintings, even if you knew nothing of his biography.

To look at one of his early paintings like Guardians of the Secret is to see the frustrations of a flawed artist and the unconcealed anguish of a perplexed human being. He imagines "guardians", powerful and remote Others, holding up a picture he can't decode, a "secret" he dearly wishes admission to - a key to art and life he does not possess. The style of the painting reveals the problems that keep him out of their club: it is manifestly derivative from Picasso.

In the 1940s New York was where European modern artists in flight from occupied France found refuge. Pollock was one of a generation of ambitious American painters, schooled in hard knocks by the Depression, who were desperate to emulate them. He was also an alcoholic with serious problems. But in 1943, the year he painted Guardians of the Secret, the collector Peggy Guggenheim started paying him monthly. His wife, the artist Lee Krasner, helped him stop drinking and, working in a converted barn at their refuge of a home on Long Island, he found a way to paint that transfigured the dream art of the surrealists into something new and marvellous.

Pollock's version of abstract art is the most exhilarating of the 20th century - more gutsy and alive than the spiritual art of Mondrian, Kandinsky or Malevich - and it gave later artists a lesson in freedom.

After this, artists could do anything. What Pollock did was to lay out huge rolls of canvas on the ground and throw, flick, pour and dribble paint on them: like a cowboy throwing out a lassoo, said his champion, the critic Clement Greenberg.

Pollock's method was wild - but he was in control of it. "No chaos, damn it!" he insisted. In his supreme works - the three cosmic abstractions of 1950 divided today between America's three greatest museums - he attains a harmony in freedom that is simply overwhelmingly beautiful and grand: a vision of an art and a life that might be, an improvised utopia, like a sax solo in paradise. You see something limitless and infinite in this art - and then the door closes. Pollock hit the bottle again. His personality crumbled. His last works are romantic ruins. (JJ)

Pontormo - Deposition (c1526-8), Portrait of a Halberdier (1529)

The fragile coloured forms wafting in the violet air of Pontormo's incredible Deposition are "bodies" only in the most perfunctory sense: the people grieving for Christ in their cascade of red and pink and blue draperies that crinkle like crêpe paper in the picture's shallow box are creatures of pure emotion, enfleshed by colour.

His young soldier is tenderly portrayed in his idealism and good looks - fodder for the cannon. (JJ)

Nicolas Poussin - Et in Arcadia Ego (late 1630s), Landscape with a Man Killed by Snake (1648), Self-Portrait (1650), Blind Orion Searching for the Rising Sun (1656), A Dance to the Music of Time (date unknown)

Poussin was a great landscape artist, but painting views with topographical accuracy was not the point.

These are enchanted environments, depicted with a balance of composition that makes them seem otherworldly. The subjects, too, are not of our time and place, often referring to classical literature, as in Et in Arcadia Ego, in which nymphs and shepherds straight out of Virgil's Eclogues curiously investigate a tomb and come face to face with mortality.

Or the utterly strange and bewitching Blind Orion, in which the giant hunter of mythology, having been blinded, seeks the rays of the sun, which will restore his sight. Death, too, interrupts the Landscape with a Man Killed by Snake: in the foreground a python-like creature overcomes a man, and fear seems to fan out from him, affecting the figures towards the background each in turn.

Sometimes Poussin is regarded as a "difficult" painter, appreciation of whom is supposedly dependent on an encylopedic knowledge of ancient literature, philosophy, and the Bible, not to mention 17th-century French politics. That is to underestimate the pleasure of simply encountering and enjoying the poetry of his subjects and the harmony of his compositions.